High-Performance Thin-Film Composite Forward Osmosis Membranes via Metal–Organic Framework/Cross-Linked Polyethylenimine Modification of Nanofiber Substrates

Developing thin-film composite (TFC) forward osmosis (FO) membranes with excellent water permeability and high selectivity is critical to FO advancement and application. Herein, a high-performance TFC FO membrane was constructed by cross-linking polyethylenimine (PEI)/zeolitic imidazolate framework (ZIF)-L with glutaraldehyde (GA) on a hot-laminated electrospun nanofiber substrate, followed by interfacial polymerization to form a polyamide (PA) selective layer. The introduction of ZIF-L/PEI/GA regulated m -phenylenediamine adsorption and diffusion, promoting a thin and dense PA layer. Moreover, ZIF materials introduced additional water channels, and ZIF-L nanosheets provided a larger localized reaction interface than that of ZIF-8 nanoparticles, which facilitated the formation of a continuous and intact PA layer. The best-performing M-ZIF-L-0.2 membrane attained a water flux of 37.6 L m –2 h –1 with a low reverse salt flux of 3.4 g m –2 h –1 using deionized water as the feed solution and 1.0 mol/L NaCl as the draw solution in FO mode and also exhibited good long-term stability. In this way, a convenient and effective approach is established for the fabrication of high-performance FO membranes.